Method of treating metal articles



LMTLE M. BENTLEY METHOD OF TREATING METAL ARTICLES Filed July 13, 1923 Patented Nov. 1, 1 927.

'unrr azi) STATES assrenon T r'acxnnn MOTOR can, com- A CORPORATION or mcnman.

METHOD OF TREATING METAL ARTICLES.

Application filed July 13,

The present invention relates to a method of securing an alloy or a metal to a portlon only of the surface of a metal member, and the product of such method.

It has been proposed to treat metal members or articles to render them immune to the effect of certain elements, for example, it has been proposed to treat iron or steel articles to render them immune to atmos- 0 pheric moisture, that is to say, to render them rustless.

According to the present invention, 1t has been discovered that certain alloys such as Babbitt metal, and certain metals such as ticle so treated. The present invention aims to provide a process whereby such alloy or metal may be secured to the metal member or article.

For purposes of illustration, the invention will be described in connection with the manufacture of iron or steel connecting rods,

although it is to be distinctly understood that the invention is not thus limited but includes the manufacture of other articles.

The objects and features of "novelty of the invention will be apparent from the de scription taken in connection with the drawings, in which:

Fig. 1 is a side elevation of a connecting rod forging;

Fig. 2-is alongitudinal section through the connecting rod shown in Fig. 1, in a plane at right angles thereto;

Figs. 3 and 4 are views corresponding to, Figs. 1 and 2 respectively, of a connecting rod after treatment and rough machining in preparation for the formation of the Bab' bitt metal bearing thereon, and Figs. 5 and 6 are views corresponding to Figs. 3 and 4 respectively, illustrating further steps in the manufacture of a connectin rod.

. Tn the manufacture of connecting rods 5 for internal combustion engines, the rod forgings, after suitable heat treatment, and

straightening. are rough machined, preparatory to babbittiifg the bearing. at the large end thereof. These forgings are then usually treated with an acid flux and tinned, after which suitable mandrels are placed in the end of the rod and the annular space around the mandrels is filled with molten Babbitt metal, poured from a suitable ladle,

Babbitt metal will stick.

1928. Serial No. 651.437. r

to form the bearing surfaces required. The tin is applied to form a surface to which PATENT OFFICE;

MARK BENTLET, DETROIT, MICHIGAN, PANY, OF DETROIT, MICHIGAN,

the Babbitt metal will readily adhere, and

the best method of applying this coat of tin is .to dip the connecting rod in an appropriate tinning bath.

This procedure has heretofore resulted in coating with tin, more of the rod surface than is to be babbitted, and subsequently, during the casting of the bearing, the Babbitt metal at the end of the pouring opera-- tion overflows onto the rod and adheres firmly thereto. This excess Babbitt metal must be removed from the'rod before pro- 5 tin, will not adhere to an iron or steel arceeding with the finishing machine Operations thereon. In usual practice, the excess metal is removed by theuse of revolving,

power driven, wire brushes and in some cases by filling or scraping by hand With a hard instrument. Such methods require consid erable time, and the brushes Wear rapidly, so that this removal of excess metal becomes an expensive part of the process.

In the present invention, those parts of the connecting rod on which the Babbitt metal is not desired are given a coating of material to which neither the tin nor the The invention also consists in the discovery that neither Babbitt metal nor tin will stick to a surface coated with basicphospha'te of iron. -More specifically therefore, the. invention consists in forming on certain parts of the connecting rod a-coating of basic phosphate of iron, and in then applying the tin and the Babbitt metal in the usual manner.

lVith reference to the drawing, at 10, Figs. 1 and 2, is shown a connecting rod forging which has received suitable heat treatment and has been straightened to correct any warping or twisting incurred during the cooling of the piece. The forging an aqueous bath of ferric acidphosphate,

preferably containing from one-half to one per cent of this salt, the bath being usually maintained at substantially a boiling temperature. The surfaces of the forging 1O become black as the basic phosphate of non is formed, the reaction being accompanied by the escape of hydrogen gas.

After the formation of the protective coat ing is completed, the forging 10 is removed from the bath, and is machined to remove the coating from those portions to wh1ch the Babbitt metal is 'to be applied. As shown in Figs. 3 and 4, this machining consists in drilling the large end 12 of the forging 10 to form a hole 14 of appropr1ate size, the sides of the piece being also machmed to form faces 16 adjacent the hole 14; The inner surface of the hole 14 is also preferably formed with a number of circumferential grooves 17, which assist in retaining the Babbitt metal. It will be evident that this machining operation removes the protective coating, that is, the basic iron phosphate, from those portions of the piece to which the Babbitt metal must adhere, exposing the bare metal, while the integrity of the coating over the remainder of the piece is undisturbed.

The piece is next treated with an acid flux and is then plunged into a suitable tinning bath in the ordinary manner. As previously stated, the tin will not adhere to the surface of iron phosphate, so that this operation results in a coating of tin over the exposed parts of the piece which have been machined, the remainder thereof being unaffected. The tin is applied to form a surface to which the Babbitt metal will more readily adhere.

After the tinning operation, a suitable mold is placed in position to cooperate with 'the large end of the rod, and the molten Babbitt metal is poured in the usual manner.

Any ofthe Babbitt metal which overflows onto the rod will not, however, adhere thereto, because of the coating of baslc iron phosphate. The pouring of the Babbitt metal,

therefore, results in the formation of an annular bearing 18, which is strongly adherent to the tinned surfaces against which it is cast. The rod is then ready for the finishing operations, such as those by which the bolt lugs 19' are provided with faces 21 and bolt holes 22, and the small end of the rodis drilled as at 23, and faced as at 24, for the usual piston pin bushing. I

It will be evident that this invention provides a simple, inexpensive and reliable process by which an alloy such as Babbitt metal may be secured to certain portions of metal articles, without necessitating the subsequent expensive cleaning of alloy from surfaces of the piece, where it is not desired. The invention also provides a convenient of tin may be applied to certain desired portions of iron and steel articles by the dipping or washing process, without covering the remainder of the article with this metal.

Although a specific method has been described, it is to be understood that the invention is not thus limited, but includes modifications and changes which come within the scope of the appended claims.

What is claimed is:

1. The method of securing an alloy to a portion only of the surface of a metal member to which the alloy normally adheres, consisting in treating the member to change the metal at and adjacent its external surface into a different chemical substance forming a coating to which the alloy will not adhere, operating on said portion of the surface of the member to remove said coating, and applying the alloy in molten form to said portion of the surface.

2. The method of attaching an alloy to a portion only of the surface of an iron or steel article to which the alloy normally adheres, consisting in treating the article to change the iron or steel at and adjacent its external surface into a different chemical substance forming a coating, to which the alloy will not adhere, operating on said portion of the surface of the article to remove said coating, and applying the alloy in molten form to said portion of the surface.

3. The method of attaching an alloy to a portion only of the surface of a metal member to which the alloy normally adheres, consisting in treating the member to change the metal at and adjacent its external surface into a different chemical substance forming a coating to which the alloy will not adhere, operating on said portion of the surface of the member to remove said coating, tinning said surface and applying the alloy in molten form to the tinned surface.

4. The process of applying Babbitt metal to portions of iron and steel articles which consists in first forming on the article a coating of basic iron phosphate, then in removing said coating from the portions to be babbitted, and thereafter casting Babbitt metal against said ortions.

5. The process 0 applying Babbitt metal to portions of iron and steel articles which consists in first forming on the article a coating of basic iron phosphate, then in removmg said coating from the portions to be babbitted, then coating said portions with tin, and thereafter casting Babbitt metal against said portions.

6. The process of applying Babbitt metal to portions of iron and steel articles which consists in first forming on the article a coatin; of basic iron phosphate, then in remov- 1H0 said coating from the portions to be aha bitted, then fiuxing and tinning said portions, and thereafter casting Babbitt metal against said portions.

iii

maven 7. The process of applying Babbitt metal to portions of iron and steel articles which consists in first immersing the articles in a solution of ferric acid phosphate to form a surface of basic phosphate of iron thereon, then removing the basic phosphate of iron from the said portions of the articles, then immersing the articles in a tinning bath to form a coating of tin on the said portions,

and finally in pouring molten Babbitt metal against the said portions.

8. The process of timing certain portions of iron and steel articles which consists in forming a surface coating of basic phosphate of iron on the entire article, removing said surface coating from the portions to be tinned, and then immersing the article in a tinning bath.

9. The process of tinning certain portions of iron and steel articles which consists in forming a surface coating of basic phosphate of iron on the other portions of the" article, gndhthen immersing said article in a tinning 10. The process of tinning certainportions of metallic articles which consists in forming on the entire article a surface coatingof a metallic salt to which tin will not stick, re-

' moving the surface coating from said certain portions of the article, and immersing the article in a tinning bath.

11. The process of tinning portions of iron and steel articles which consists in immersing the articles in a solution of ferric acid phosphate, then machining the portions to be ted, and then immersing the articles in a tinning hath,

12. The process of tinning portions of iron and steel articles which consists in immersing the 111w in a boiling aqueous solution containing about one percent of ferric acid hosphate, then machining the portions to 1 e tinned, and then immersing the articles in a tmn' ing bath.

13. The process of tinning portions of iron and steel articles which consists in immersing the same in a solution of ferric a'cid' hos hate, then machinin the portions to e tinned, then fluxin t e articles in an acid bath, and finally immersing the articlgs.

c the article a coating of a metallic salt towhich Babbitt metal will not adhere, removing the coat-in from the said certain portions, and therea ter casting the Babbitt metal against said portions.

16. The process of preparing a connecting rod forging for the reception of Babbitt metal hearings which consists in firstwashing the forging to remove dirt therefrom,

then forming on the surface of the forging a coating of basic iron phosphate, then machining the bahhitt receiving portions of the forging, then dipping the forging in a tinning bath, and final y casting the Babbitt metal in position on said forging.

In testimony whereof I afix my signature.

MARK BENTLEY. 

